Light may increase magnetic memory speeds 1000 times, decrease electricity consumption Explore further Citation: Disorder helps to ‘hyperfocus’ waves in time reversal acoustics (2006, March 24) retrieved 18 August 2019 from https://phys.org/news/2006-03-disorder-hyperfocus-reversal-acoustics.html “This is the first time that a time reversal experiment has been performed through a phononic crystal, i.e. a perfectly ordered material,” said Tourin. “The comparison between a phononic crystal and a disordered medium shows that disorder plays a clear role in the so-called ‘hyperfocusing effect.’”The team of physicists also analyzed time-reversal properties for short-lived evanescent waves that occur at forbidden frequencies in the phononic crystal. The evanescent waves exhibited surprisingly good time compression, showing that – despite the absence of hyperfocusing – time reversal focusing is still possible in highly ordered media.Since conventional sound waves disperse when traveling through a medium, the possibility of focusing sound waves could have applications in several areas. In cryptography, for example, when sending a secret message, the sender could ensure that only one location would receive the message. Interceptors at other locations would only pick up noise due to unfocused waves. Other potential uses include antisubmarine warfare and underwater communications that benefit from targeted signaling.Citation: Tourin, A., Van Der Biest, F. and Fink, M. Time Reversal of Ultrasound through a Phononic Crystal. Physical Review Letters 96, 104301 (2006).By Lisa Zyga, Copyright 2006 PhysOrg.com For every burst of sound, there must exist a sound that bursts in reverse, according to the theory of time reversal acoustics. From their discoveries of some surprising characteristics of mediums and frequencies, scientists have gained insight into acoustic time reversal, which could impact applications such as sending confidential messages in cryptography. This sketch shows how a disordered medium can “hyperfocus” sound waves – something that an ordered medium cannot do. A disordered medium acts like an acoustic lens, its heterogeneities refracting sound waves by scattering and directing otherwise-lost wave frequencies (red arrows) toward the time reversal mirror (TRM). In an ordered medium, on the other hand, the wave frequencies are not scattered (blue arrows), and therefore only those already heading toward the TRM are received. Credit: A. Tourin, et al. The team used a TRM that consisted of an array of 41 transducers, which recorded the original waves and then focused the waves back to the source. The transducers play the role of microphones and loudspeakers because they act as “reversible” devices.“The term ‘time reversal’ tells you that the signal captured by the TRM and stored in electronic memories is read in the reverse order before being sent back,” Tourin told PhysOrg.com.Although the 41 transducers try to capture as many of the original waves within a phononic (vibrating) crystal as possible, several frequencies slip through the cracks, which reduces spatial focusing for the return waves. Sometimes, frequencies that would normally not pass through the TRM can be directed toward the mirror by a medium with large apertures and significant disorder.In this case, when the 41 transducers try to capture waves propagating through a medium of steel rods arranged randomly in water, the rods scatter and redirect otherwise-lost frequencies into one of the transducers. The ability to catch these misguided frequencies is called “hyperfocusing.” When the physicists observed time reversal in a phononic crystal, however, they did not observe the hyperfocusing effect. Time-reversed focusing is based on the fact that when a wave is played backwards in time, wavelengths will retrace their paths. Although theoretically the overlap should be exact, the actual time reversal mirrors (TRMs) that play back the waves can not “catch” every frequency of the original wave. Scientists know that some media allow acoustic time reversal to occur with higher resolution than other media, and recently physicists from the University of Paris have discovered how disordered and ordered media affect this resolution.In a study published in Physical Review Letters, physicists A. Tourin, F. Van Der Biest and M. Fink have found that, while sound waves traveling through a disordered medium can focus with high precision, waves traveling through an ordered medium do not have the same ability to focus. The team was also surprised to discover that for a certain type of wave called evanescent waves, an ordered medium exhibits better time compression than a disordered medium. Using this phononic crystal, physicists found that a medium with an orderly lattice arrangement exhibits better time compression (the signal recorded at the original source) than a disordered medium in time-reversed evanescent sound waves. Better time compression gives a closer approximation of the initial sound. Credit: A. Tourin, et al. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
The major components of a net-zero energy home as part of GE’s Net-Zero Energy Home project.Credit: General Electric. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: General Electric Plans Net-Zero Energy Home by 2015 (2009, July 16) retrieved 18 August 2019 from https://phys.org/news/2009-07-electric-net-zero-energy-home.html Explore further (PhysOrg.com) — Using solar panels, wind turbines, appliance monitoring, and on-site energy storage, General Electric has a plan to enable homeowners to cut their annual energy consumption (from the electric grid) to zero, in some cases, and at least minimize consumption in others. GE is piloting the technology this year, and hopes to commercialize the system by 2015. Californians bask in solar energy The GE Net-Zero Home Project encompasses a variety of technologies, as well as consumer incentives. The most expensive part of the project involves on-site power generation through solar panels or wind turbines, where applicable. As GE executives explained during a recent symposium at the company’s Global Research Center in Niskayuna, New York, a 3,000-watt solar panel array could be enough to supply all of a home’s consumption, and cost about $30,000 to install.GE is also converting its appliances (for about $10 per appliance) to be able to communicate with a home’s smart meter, allowing consumers to find out how much energy individual appliances use. The information will hopefully allow users to control appliances by using them during off-peak times (peak times are usually morning and early evening), encouraged by time-of-use pricing plans. Homeowners would also use an energy monitoring device called Home Energy Manager, which costs about $200-250. The Home Energy Manager is designed to control and optimize on-site energy generation and consumption, such as by running the dishwasher or clothes dryer at times when the solar panels are operating, and not during peak times.As part of the project, plug-in electric vehicles would be charged during the night. The vehicles and other storage batteries could also be used to store electricity for use during peak times. Overall, a net-zero energy home would cost about 10 percent more than the conventional kind, but would help homeowners save money in the long run, as well as make the electricity grid more efficient. If the system is easy to use and offers financial incentives for customers, GE hopes that it can encourage involvement where everyone can benefit.via: CNet© 2009 PhysOrg.com
via Japantrends Explore further More information: Citation: Panasonic releases wireless solar charging table (2011, May 23) retrieved 18 August 2019 from https://phys.org/news/2011-05-panasonic-wireless-solar-table.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (PhysOrg.com) — Most of us forget how much our cell phones are a part of the day-to-day of our lives until we don’t have access to them. I’m not just talking about when you leave it at home, in a callous act of irresponsibility. An event as simple as a dead battery can mean that you miss an important call that creates ripples in your whole week. © 2010 PhysOrg.com NTT Docomo’s new smartphone features wireless charger So when you are out and your battery suddenly goes to red what are you going to do about it? Unless you happen to have an outlet in your pocket, in which case you are probably a robot, you are short on options. Or, at least you used to be. In the near future Panasonic may have a solution to your problem. They were showing off a prototype of a solar-powered inductive charging table at the Retail Tech Expo in Tokyo. The device would be able to wirelessly charge any device with a Qi battery simply by setting the device down on it. This not the first wireless charging station on the market. In 2010 Energizer put out a similar pad that relied on being plugged in to a power source. Various companies have created solar chargers for mobile devices, though most of these have been too unwieldy or too expensive to become popular. Panasonic is the first company to date to combine the two ideas and create a wireless solar charger. Panasonic did mention that these units would be on sale by the end of this year in Japan. No word has been given yet on when this device will be on sale in the United States.
(PhysOrg.com) — If you looked around at your family some 40,000 years ago, you would not have seen grandparents as the likelihood of a person passing their 30th birthday was slim. However, according to new research reported in Scientific American, 30,000 years ago things began to change and the life expectancy of adults began to rise. It is this change that anthropologist and Professor Rachel Caspari from Central Michigan University believes was a turning point for human civilization. At the same time humans were living longer, evidence shows that there was an increase in food production, artistic expression, and the creation of complex weapons and tools and the researchers contribute this to the experience of the older members of the population.The researchers looked at teeth from ancient human beings to determine the age they were at death. Throughout evolution, finding those that had lived past the age of 30 was rare. However, this changed when the researchers looked at Homo sapiens and compared them with Neanderthals. They discovered that for every 10 Neanderthals that had died at a young age, four adults survived past the age of 30. The striking difference was in the Homo sapiens where they discovered that for every 10 youngsters that died, 20 adults had reached the age of 30 or older.The effects of having an increasingly older and more knowledgeable population, the researchers believe, were the key to the survival and success of the Homo sapiens. Elder members were able to pass down the information they had learned such as foods that were poisonous and tool making skills. Elder members of the community were able to care for children while others worked to provide and gather food.While researchers do not know why it is that adults of this time began to live longer, they believe the change and the addition of older members was essential for survival. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2010 PhysOrg.com Explore further More information: Scientific American Citation: Grandparents connected to success of human race (2011, July 26) retrieved 18 August 2019 from https://phys.org/news/2011-07-grandparents-success-human.html Small horned dinosaur from China, a Triceratops relative, walked on two feet
(PhysOrg.com) — Physicists in Italy have discovered the first evidence of a rare nucleus that doesn’t exist in nature and lives for just 10-10 seconds before decaying. It’s a type of hypernucleus that, like all nuclei, contains an assortment of neutrons and protons. But unlike ordinary nuclei, hypernuclei also contain at least one hyperon, a particle that consists of three quarks, including at least one strange quark. Hypernuclei are thought to form the core of strange matter that may exist in distant parts of the universe, and could also allow physicists to probe the inside of the nucleus. The FINUDA experiment is located at one of the two interaction points of the DAFNE collider at INFN-LNF. As Elena Botta, a lead collaborator in the study, explained, DAFNE produces electron and positron beams. When these beams collide nearly head-on, they produce the phi meson (Φ), which decays with a 50% probability into a charged pair of K and anti-K mesons. FINUDA’s interaction point contains an octagonal prism with eight targets along the sides. When the anti-K meson interacts with a lithium nucleus in one of these targets, it can simultaneously produce a 6ΛH hypernucleus and a π+ meson of a particular energy. If scientists detect this particular meson, they’ve detected a signature of the strange nucleus formation. As Botta explained, 6ΛH production involves a two-step mechanism to decrease the number of protons in the lithium isotope, 6Li, from three to one, which produces hydrogen. Once produced, the neutron-rich 6ΛH hypernuclei slow down inside the target, and after 10-10 seconds they decay at rest into a π- meson and a 6He nucleus. The π- meson also has a particular energy, and scientists can easily detect it to give the signature of the decay. So both the formation and the decay of 6ΛH hypernuclei can be detected by searching for events with the presence of these particular π+ and π- mesons. Strange matterAs the first evidence for 6ΛH hypernuclei, the results could shed light on strange matter, which is hypothesized to exist at the center of ultra-dense neutron stars. The physicists hope to investigate strange matter further by producing strange nuclear systems.“Hypernuclei can be interpreted as the core of strange matter,” Botta told PhysOrg.com. “In particular, the possibility to produce strange nuclear systems containing two Λ particles will allow us to study the interaction between strange particles.”Hypernuclei could also serve as a useful tool to investigate the current model of nuclear structure, in which protons and neutrons are arranged in a stable configuration. “The fact that a hypernucleus has a strange quark does give it interesting characteristics compared to normal nuclei, since it allows the component L particle to act as a probe that can go very deep into the nucleus to test the description that the single particle shell model gives of nuclear matter,” Botta said. “In this respect, the study of hypernuclear physics allows us to get information not directly accessible otherwise.”She added that other hypernuclei with large neutron-to-proton ratios could exist in a stable state, even though ordinary neutron-rich nuclei are theoretically unstable. Neutron-rich hypernuclei seem to be an exception because of the way they modify the structure of a nucleus and increase its lifetime. During an upcoming experiment at the Japan Proton Accelerator Research Complex (J-PARC), physicists plan to search for 6ΛH as well as for other neutron-rich hypernuclei, such as lithium 10 Lambda (10ΛLi). Journal information: Physical Review Letters The particular hypernucleus investigated here, called “hydrogen six Lambda” (6ΛH), was first predicted to exist in 1963. Now, in a study published in a recent issue of Physical Review Letters, physicists working in the FINUDA experiment at the Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali di Frascati (INFN-LNF) in Frascati, Italy, have reported finding the first evidence for the particle. The FINUDA collaboration’s analysis of millions of events has turned up three events for the rare hypernucleus. Strange propertiesAs its name suggests, 6ΛH is a large type of hydrogen nucleus that consists of six particles: four neutrons, one proton, and one Lambda (Λ) hyperon. Since an ordinary hydrogen nucleus contains one proton and no neutrons, hydrogen nuclei that contain one or more neutrons are sometimes called “heavy hydrogen.” The most common types of heavy hydrogen are deuterium (which has one neutron) and tritium (which has two neutrons). Since 6ΛH has four neutrons plus a L hyperon, physicists refer to it as “heavy hyperhydrogen.”The L hyperon, which consists of one up, one down, and one strange quark, does an even more interesting thing to 6ΛH: it increases its lifetime from 10-22 seconds (the lifetime of the hypernucleus core 5H without L) to 10-10 seconds. When scientists first discovered the L hyperon in 1947, they observed a similarly longer lifetime than predicted for this “strange” object. That observation led to the idea of the existence of the strange quark, with strangeness being the property that causes the quark to live so long.DetectionWithout the L hyperon, it would likely be impossible for physicists to directly observe a hydrogen nucleus with four neutrons, since such a heavy isotope is very difficult to produce and has a very short lifetime. Another hypernucleus, 4ΛH, which has two neutrons instead of four, is more easily produced than 6ΛH in similar experiments and has been detected many times. But detecting evidence of 6ΛH is much more difficult. The 27 million collision events analyzed by the FINUDA collaboration represents about one full year of continuous data-taking from an experiment that spanned several years. Theoretically, the formation probability of 6ΛH is at least 100 times smaller than that of 4ΛH. Explore further Nuclear physics incorporates a ‘strange’ flavor More information: M. Agnello, et al. “Evidence for Heavy Hyperhydrogen 6ΛH.” Physical Review Letters 108, 042501 (2012) DOI: 10.1103/PhysRevLett.108.042501 Copyright 2012 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. A view of one of the three events found by FINUDA: a schematic frontal view of the apparatus is shown, and the two blue lines represent the two ‘pi’ mesons moving along opposite bent trajectories in the magnetic field of the apparatus. Image credit: FINUDA collaboration Citation: Physicists discover evidence of rare hypernucleus, a component of strange matter (2012, February 17) retrieved 18 August 2019 from https://phys.org/news/2012-02-physicists-evidence-rare-hypernucleus-component.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Explore further More information: www-robotics.jpl.nasa.gov/syst … system.cfm?System=11 NASA Controls an Athlete Rover LIVE at GDC with Leap Motion Controller. The ATHLETE is 13 feet. Various descriptions include “robotic lunar rover test-bed” and “legged lunar cargo robot “.as ATHLETE can unload bulky cargo Its reach is about 20 ft. (It is said that ATHLETE would be able to climb slopes up to 35° on solid surfaces and 25° on soft surfaces, such as soft deposits.The design includes six Degrees-of-Freedom limbs, each with a 1 DoF wheel attached. The wheels are designed for driving over stable terrain, but each limb could serve as a general-purpose leg, placed in an alternative walking mode, whereby the wheels could be locked and used instead as feet, over difficult terrain. Another ATHLETE feature is its limbs’ adapters, allowing tools to be drawn out and maneuvered by the limb.Luo is the Task Lead, NASA Jet Propulsion Laboratory (JPS). He leads the development of natural user interface technologies for commanding robot navigation and dexterous manipulation. Norris is Manager of Mission Planning and Execution at JPS. He is involved with the software, people, and processes that command fifteen robotic spacecraft throughout the solar system. NASA’s ATHLETE Warms Up for High Desert Run (w/ Video) “The ATHLETE (All-Terrain Hex-Limbed Extra-Terrestrial Explorer) has six legs and six degrees of freedom, six joints. What part of our body has that much manipulation power? Well, it turns out, our hands have similar dexterity. We mapped our hands to the robot; we did so using the Leap Motion device. Just for you guys today, we are going to do something special.” Credit: NASA Natural Interface Control of Future Space Robotics. Exploring future interface technologies such as the zSpace and Leap devices to drive future NASA robots such as the ATHLETE. He told the GDC audience that he and Norris would be moving the six-legged, one ton robot in the southern California laboratory via the Leap Motion device with them onstage at the GDC event in San Francisco. Mission successful. The robot responded, reacting to finger and wrist movements. The audience at the Moscone Center watched all this on a big screen. ATHLETE’s purpose, as an R&D project at NASA, is to behave as a support for human exploration in extreme environments—the moon, Mars, and beyond. Norris sees a day when humans can use devices like Leap Motion to explore the universe remotely. Said Norris, “I want us to build a future of shared immersive tele-exploration, everyone exploring the universe through robotic avatars alongside our astronauts…stepping inside a holodeck and standing on those distance worlds.” © 2013 Phys.org (Phys.org) —NASA representatives were at the 2013 Game Developers Conference (GDC) in San Francisco to show how the ATHLETE robot, a six-legged robot developed at the Jet Propulsion Laboratory in southern California, can move via remote control with the Leap Motion device. Victor Luo and Jeff Norris, from the Jet Propulsion Lab in Pasadena, presided over the demo. Luo told the audience of game industry professionals: Citation: NASA uses Leap Motion to move ATHLETE rover (w/ video) (2013, April 1) retrieved 18 August 2019 from https://phys.org/news/2013-04-nasa-motion-athlete-rover-video.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Geologists discover ancient buried canyon in South Tibet Citation: Research trio suggest low-relief mountain surfaces due to river network disruption (2015, April 23) retrieved 18 August 2019 from https://phys.org/news/2015-04-trio-low-relief-mountain-surfaces-due.html More information: In situ low-relief landscape formation as a result of river network disruption, Nature 520, 526–529 (23 April 2015) DOI: 10.1038/nature14354AbstractLandscapes on Earth retain a record of the tectonic, environmental and climatic history under which they formed. Landscapes tend towards an equilibrium in which rivers attain a stable grade that balances the tectonic production of elevation and with hillslopes that attain a gradient steep enough to transport material to river channels. Equilibrium low-relief surfaces are typically found at low elevations, graded to sea level. However, there are many examples of high-elevation, low-relief surfaces, often referred to as relict landscapes, or as elevated peneplains. These do not grade to sea level and are typically interpreted as uplifted old landscapes, preserving former, more moderate tectonic conditions. Here we test this model of landscape evolution through digital topographic analysis of a set of purportedly relict landscapes on the southeastern margin of the Tibetan Plateau, one of the most geographically complex, climatically varied and biologically diverse regions of the world. We find that, in contrast to theory, the purported surfaces are not consistent with progressive establishment of a new, steeper, river grade, and therefore they cannot necessarily be interpreted as a remnant of an old, low relief surface. We propose an alternative model, supported by numerical experiments, in which tectonic deformation has disrupted the regional river network, leaving remnants of it isolated and starved of drainage area and thus unable to balance tectonic uplift. The implication is that the state of low relief with low erosion rate is developing in situ, rather than preserving past erosional conditions.Press release (Phys.org)—A trio of researchers, two with the Swiss Federal Institute of Technology and the other with Ben-Gurion University of the Negev, claim to have found evidence that suggests low-relief mountain surfaces are due to river disruption, not tectonic uplift. In their paper published in the journal Nature, Rong Yang, Sean Willett and Liran Goren describe how they showed that a portion of the Tibetan Plateau likely did not come about due to tectonic uplift and instead suggest an alternative explanation. Jérôme Lavé with Centre de Recherches Pétrographiques et Géochimiques in Rome offers a News & Views piece on the work done by the trio in the same journal issue. This beautiful scenery in Yunnan Province, China, at 3000 m asl is not likely a time capsule that preserved a relict lowland landscape. It must have formed over million of years in situ. Credit: Giuditta Fellin / ETH Zurich For many years geologists have puzzled over flat plains that exist at high altitude in mountain ranges. Common sense suggests mountains should be jagged, especially those that formed due to pressure between the Earth’s plates. Over the years, a grudging consensus has been reached—the flat plains must have got to where they are by simple uplifting—whole sections of flat earth were pushed up intact, along with the other parts of the mountain as plates collided. This idea has not been wholly embraced of course, because in many ways it seems to defy logic. In this new effort, the three researchers started out as skeptics, in looking at a part of the Tibetan Plateau known as the “Three Rivers Region”—where the Yangtze, Mekong and Salween rivers incise the plain, they could not find a way to simulate the area being uplifted, so they began to look for another explanation. To do that, they input geologic data that describes the area into a model, one that took into account the unexpectedly shallow tributaries in some parts of the Plateau and also others that were steeper—evidence, they suggest, of recent drainage.The model the trio came up with shows that the Plateau came about due to a reorganization of the river network after uplift, because parts of them became isolated. Subsequent erosion of the resultant landscape led to the flat terrain as it can be seen today. Lavé allows that the model does show what the trio suggest, but also notes that it does not seem to work as well when shifting the focus farther north in the region. He suggests future modeling should take into consideration the new findings, however, as it appears the research trio have come up with a new way of thinking about low-relief mountain surface formation. Explore further © 2015 Phys.org Journal information: Nature This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
, arXiv PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen Journal information: Physical Review Letters This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Play Drops of cold liquid SF6SF6 fall through an atmosphere of helium gas containing SF6SF6 vapor. Each drop, by cooling the surrounding vapor, creates a burst of tiny SF6SF6 droplets in its wake. The experiment illustrates a basic process of droplet seeding that may contribute to rain formation in the Earth’s atmosphere. Credit: P. Prabhakaran et al., Phys. Rev. Lett. (2017) They report that some of the sulphur hexafluoride pooled at the bottom of the tank and some of it remained as a gas in the upper portions of the tank. But then, the sulphur hexafluoride began to form droplets on the top of the box, which eventually detached, falling through the gas to land in the pool below. But the team found that as they fell, they caused smaller droplets to form in their wake—this was because the drops were colder than the gas they were passing through. These smaller drops than fell into the pool below as rain.The researchers acknowledge that they have no evidence that their experiment mimicked nature, but note that if something similar is happening in the atmosphere, it could explain the onset of sudden rainstorms. © 2017 Phys.org Contrast enhanced image sequence of an SF6 drop falling through the gaseous SF6-He layer. Shown is the lower part of the cell. The black mark on the left indicates the position of the liquid-vapor interface located at about 6 mm from the bottom plate. The time stamp (in ms) for each of these figures is indicated at the bottom right corner. Credit: arXiv:1705.10501 [physics.ao-ph] Drops of water found to spring from oscillating surface faster than the surface moves A half-century ago, scientists discovered that dumping dry ice on top of cumulus clouds caused the clouds to release rain, but to this day, nobody knows why. Similarly, scientists are still baffled by sudden rainstorms. Why do some clouds suddenly release rain while others that appear nearly identical do not? No one knows, because the factors at play in rain clouds are too difficult to study. For that reason, scientists are trying to recreate atmospheric conditions in the lab or via computer simulations. Unfortunately, neither approach has led to answers regarding sudden rainstorms. In this new effort, the researchers have taken a new approach to better understand rainstorms.Because it is difficult to mimic normal upper atmospheric conditions in a lab container, the researchers chose to use sulphur hexafluoride as a stand-in for water in the atmosphere because it can exist as a liquid and a gas at surface level pressure and also because it forms into droplets when chilled. They used helium as a stand-in for general atmospheric gasses. The chemicals were pumped into a box which was then heated slightly on the bottom and chilled slightly at the top. The researchers used a high-speed camera to film the action. (Phys.org)—A team of researchers from Germany, France and the U.S. has found a possible explanation for the onset of sudden rainstorms. In their paper published in the journal Physical Review Letters, the group describes experiments they conducted with stand-ins for water and atmospheric gases in a box in their lab and what they witnessed. More information: Prasanth Prabhakaran et al. Can Hail and Rain Nucleate Cloud Droplets?, Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.119.128701 , On Arxiv: https://arxiv.org/abs/1705.10501AbstractWe present results from moist convection in a mixture of pressurized sulfur hexa-flouride (liquid and vapor) and helium (gas) to model the wet and dry components of the earth’s atmosphere. To allow for homogeneous nucleation, we operate the experiment close to critical conditions. We report on the nucleation of microdroplets in the wake of large cold liquid drops falling through the supersaturated atmosphere and show that the homogeneous nucleation is caused by isobaric cooling of the saturated sulfur hexaflouride vapor. Our results carry over to atmospheric clouds: falling hail and cold rain drops may enhance the heterogeneous nucleation of microdroplets in their wake under supersaturated atmospheric conditions. We also observed that under appropriate conditions settling microdroplets form a rather stable horizontal cloud layer, which separates regions of super and sub critical saturation. Citation: Experiment in a box suggests a few cold falling rain drops could lead to a rain shower (2017, September 28) retrieved 18 August 2019 from https://phys.org/news/2017-09-cold-falling-shower.html Explore further
Artist’s impression of a supermassive black hole. Credit: NASA/JPL-Caltech Italian astronomers have conducted an X-ray analysis of the accreting supermassive black hole in the broad line radio galaxy PKS 2251+11 as part of a study aimed at investigating the galaxy’s nuclear environment. The new research, presented in a paper published March 15 on arXiv.org, could improve the understanding of active galactic nuclei. Radio galaxies, which have active galactic nuclei (AGN), emit huge levels of radio waves from their central cores. Black holes at the center of these galaxies are accreting gas and dust, generating high-energy jets visible in radio wavelengths, which accelerate electrically charged particles to high velocities. In AGNs, the accreting material is reprocessed by the surrounding nuclear environment, so that these objects are observable at all wavelengths, from radio to gamma-rays. However, the structure of the nuclear environment still baffles scientists, and more studies, especially in the X-ray wavelength, are required in order resolve any uncertainties regarding this subject. Such observations could be a powerful tool for the investigation of the accretion-ejection physics in the neighborhood of supermassive black holes in AGNs.Broad-line radio galaxies (BLRGs), like PKS 2251+11 at a redshift of approximately 0.33, are excellent targets for high-quality X-ray observations due to the fact that they have the highest X-ray fluxes in the radio-loud population of AGNs. Therefore, high X-ray luminosity and the relative proximity of PKS 2251+11 make it an ideal candidate for a detailed analysis of the accretion regions in radio galaxies.So a group of astronomers led by Samuele Ronchini of Gran Sasso Science Institute in Italy has used ESA’s XMM-Newton space telescope to conduct spectral and timing analysis of PKS 2251+11 in the X-ray band in order to get more insight into the structure, kinematics and physical state of the nuclear environment in this galaxy.”Through the X-ray analysis of an observation performed with the XMM-Newton observatory, we have obtained novel information about the geometry, the kinematics and the physical state of the regions surrounding the accreting SMBH [supermassive black hole] at the center of the BLRG PKS 2251+11,” the astronomers wrote in the paper.The observations found that the X-ray source in PKS 2251+11 is partially covered by the ionized absorbing medium. This absorber is most likely clumpy and could be composed by distinct clouds with a covering factor of around 90 percent. The distance of the absorbing medium from the supermassive black hole was estimated to be around 0.33 light years, however, it cannot be excluded that the absorber is located much farther, in the zone of the dusty torus.The researchers also detected an iron K-alpha emission line at 6.4 keV. The intensity of this emission showcases variability on timescales of hours. The scientists added that besides this feature, no other spectral parameters exhibit significant variability during the observational campaign.In concluding remarks, the authors of the paper noted that many questions remain about PKS 2251+11, like the origin of its jet. This is mainly due to the lack of information regarding the state of the very innermost disk and the spin of the galaxy’s SMBH. However, the researchers note that the X-ray properties indicate that PKS 2251+11 does not differ significantly from the non-jetted AGNs. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2019 Science X Network More information: Samuele Ronchini et al. X-ray analysis of the accreting supermassive black hole in the radio galaxy PKS 2251+11. arXiv:1903.06611 [astro-ph.HE]. arxiv.org/abs/1903.06611 Explore further Bright X-ray galactic nuclei Citation: Astronomers investigate supermassive black hole in the radio galaxy PKS 2251+11 (2019, March 27) retrieved 18 August 2019 from https://phys.org/news/2019-03-astronomers-supermassive-black-hole-radio.html
Stand-up comedy gets a facelift with comedian and writer Sorabh Pant showcasing an interesting piece The Travelling Pants, his travelogue, in Delhi.Giving an extensive insight into his travel experiences, Sorabh has collated this interesting act. Talking about the act, he said: ‘It is a stand-up comedy show about travelling across India and the world. It’s a lot of material that I’ve collected over the last year in Mumbai and abroad. So expect some ridiculous insights into people and travelling quirks and airport announcements and racism.’ Also Read – ‘Playing Jojo was emotionally exhausting’So get ready for an 80 minute complete joyride, as Pant covers travel across India, abroad and even that in Delhi, in the process explaining why Bihar is an amusement park, why in America milk rules, why Spanish people are molesters and what lingo improves travel in north India. Asked how he came up with the idea for the show, Pant explained: ‘I’ve always been interested in travel mainly because I’m married. So any excuse to get away is welcomed by both me and my wife! I’ve been writing about travel constantly and been trying to find the humour in the ridiculous ways of people. Whether it’s the Spanish throwing tomatoes at each other for fun or Delhiites being reluctant to give directions, Bengalis obsessed with the age of their restaurants, Biharis trying to parcel their silly tourism as an amusement park or even how uncomfortable it is for Jains in a land like South Africa where fish is vegetarian.’ Also Read – Leslie doing new comedy special with Netflix‘Also, stand-up comedy has taken me to a few countries. I just toured Canada, US and Dubai and all the madness there flew into this special. I love to travel. I love to make jokes. The combination was magic!’ he added.So how many places has he covered in his ‘pants’? ‘Even before I turned nine I had been to Europe and most of India. With my family I’ve travelled to about four continents. So, The Travelling Pants is probably my whole family. In total I think I’ve been to about 23 countries and a lot of Indian states. My passport is quite travel weary, I think I should be like Dawood Ibrahim and get four extra ones for fun! We love travelling so much my wife and me decided to spend our honeymoon bumming a trip to Bhutan with the whole family. Our honeymoon was our family moon!’ said Pant.DETAILAt: Epicentre, Gurgaon When: 2 December; Tickets: Rs 400, 300, 200